1. Field of the Invention
The present invention relates to an ink composition and inkjet recording method.
2. Description of the Related Art
Inkjet systems, in which ink is discharged as droplets from an ink discharge orifice, are employed in many printers for reasons such as small size, low cost, and an ability to form an image without contacting a recording medium. Among these inkjet systems, a piezo inkjet system, in which ink is discharged by utilizing deformation of a piezoelectric element, and a thermal inkjet system, in which droplets of ink are discharged by utilizing the phenomenon of boiling of the ink by means of thermal energy, are characterized by their high resolution and high speed printing properties.
In recent years, inkjet printers have not been limited only to photographic printing and document printing for home use or office use, and the development of commercial printing equipment and industrial printing equipment employing inkjet printers has been carried out.
In contrast to conventional inkjet ink compositions and inkjet recording methods for home use or office use, there is a strong requirement for inkjet ink compositions and recording methods intended for use in commercial printing equipment or industrial printing equipment to have wide color reproduction in a formed image, and an excellent prolonged discharge reliability.
Furthermore, JP-PCT-2000-504778 (JP-PCT denotes a published Japanese translation of a PCT application) discloses a radiation-curable inkjet composition comprising 80% to 95% by weight of polyfunctional alkoxylated and/or polyfunctional polyalkoxylated acrylate monomer, and a photo polymerization initiator.
Furthermore, JP-A-2004-2528 discloses a UV-curable ink composition for inkjet recording consisting at least of a yellow pigment, a photopolymerizable compound, and a photopolymerization initiator, wherein the ink composition comprises C.I. pigment yellow 180 as the yellow pigment and a polymeric dispersant having a basic absorbing group, and JP-A-2005-105225 discloses an actinic radiation-curing ink-jet ink composition comprising a photo-acid generator, a photopolymerizable compound and a pigment, wherein the photo-acid generator is an onium salt which does not produce benzene by irradiation with actinic radiation, the photopolymerizable compound is a compound having the oxetane ring, and the pigment is at least one selected from the group consisting of C.I. (Color Index) PY74, PY93, PY120, PY128, PY138, PY139, PY151, PY166, PY180, PY185, PR122, PR177, PV19, PB15:3, PB15:4, and PBk7.